Host response in tumor growth and progression

Area of Science:

• Oncology
• Mathematical Biology
• Systems Biology

Background:

• Tumor growth is influenced by complex controls, including growth factors (GFs) secreted by the tumor.
• Tumors can adapt to environmental conditions, such as hypoxia, by upregulating angiogenic signals like basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF).
• These signals suggest tumors may actively manipulate their surrounding environment to promote growth.

Purpose of the Study:

• To investigate how the host responds to tumor-derived signals.
• To determine the linkage between the host's response and tumor growth.
• To explore the impact of different host response functions on tumor growth dynamics and stability.

Main Methods:

• Development of an idealized mathematical model of tumor growth incorporating adaptive signals.
• Characterization of host response using a function representing the host's carrying capacity for the tumor.
• Analysis of system stability for various candidate host response functions, where instability correlates with infinite tumor growth.

Main Results:

• A constant host carrying capacity limits environmental control to tumor shape and signal processing.
• A host response that increases carrying capacity in reaction to tumor signals creates a positive feedback loop, potentially leading to unstable tumor growth.
• Analysis of specific response functions reveals conditions for system stability and instability.

Conclusions:

• The nature of the host's response significantly influences ultimate tumor growth.
• Positive feedback in host response can drive 'infinite' tumor growth, representing an unstable state.
• Countervailing negative feedback signals are crucial for maintaining tumor stability.